Do-It-Yourself Airplane Maintenance

Steve Ells

Take out your pilot logbook. Have you logged fewer hours this year? A slow economy will do that. Making the decision to pump that disposable income — don’t you love that term? — into your airplane’s fuel tank can be difficult, especially when the disposable-income pool isn’t what it used to be. Yet if airplanes aren’t flown, airplane maintenance costs almost always increase. When money’s tight, something has to give, and it’s usually flying time.

"One of the most important things an owner can do to cut maintenance costs costs is keep flying or pickle the engine if it's not flying," says Phil Kirkham, a 25-year airframe and power-plant mechanic (A&P) who specializes in private-aircraft maintenance and is owner of Coastal Valley Aviation in Santa Maria, California.

Kirkham says that in the long run, inactivity causes maintenance costs to go up, mainly because it increases the likelihood of engine rust and because the seals in assemblies such as shock struts, brakes and fuel selector valves are more apt to need replacement.

One way to get more out of the flying budget is to get involved in hands-on airplane maintenance. I'm talking oil, wrenches, safety wire, green nitrile gloves, screwdrivers and safety wire. Federal aviation regulations (FAR) permit owners to perform and sign off on a number of preventive maintenance (PM) tasks on their own aircraft. Preventive maintenance includes changing the engine oil and filter, changing landing-gear tires, greasing wheel bearings, changing landing light bulbs and navigation light bulbs and lubricating the airframe.

Less obvious PM tasks include changing side windows, servicing landing gear shock struts with oil, air or both, making simple fabric repairs, patching fairings, cowlings and cover plates and repairing landing-light and navigation-light wiring.

Today's digital avionics systems store catalogs of navigation and communication data that IFR fliers must update every 28 days. Preventive airplane maintenance rules allow owners to upgrade these databases.

Owners are also allowed to remove and replace (R & R) front instrument panel-mounted navigation-communication (navcom) units. This includes almost all modern navcoms and many GPS navigators.

Even the lowly task of cleaning saves money.

Cleanliness Is Next to Airworthiness At each annual inspection, the regulations mandate that the airplane be cleaned. No mechanic likes this task, but it must be done before inspecting the airplane. Your mechanic will greet you with a smile, and the inspection phase of the annual will go faster when you show up with a clean airplane. Here's a tip for cleaning the belly. Head for a hardware or auto-parts store and get a tub of GOJO — the nonabrasive type, please — a creeper, a pair of safety goggles, a box of throwaway nitrile gloves and some rags. Then get under your airplane and do the "wax on, wax off" routine from nose to tail.

Avionics Money Savers Don Dominguez owns San Luis Avionics in San Luis Obispo, California.

"One of the easiest things owners can do to take care of their avionics is keep the antennas clean," says Dominguez.

"I've had to repair more than one transponder because the antennas were so oil-soaked that the metallic components in the engine oil shorted the antenna to the airframe," says Dominguez.

Dominguez says that pilots should periodically turn all rotating avionics switches through the full range of travel. This wipes oxidation off the contacts on the wafer-type switches. This is especially true for VFR pilots who rarely move their transponder code knobs from the 1200 position.

Headset plugs should be cleaned when audio gets scratchy or when the ATC has trouble hearing transmissions.

"Just polish up the plugs with a piece of fine Scotch-Brite," says Dominguez.

Dominguez advises each of his clients to do his or her own avionics database's updates. All that's required is a computer with an Internet connection and a subscription to access downloads from the avionics manufacturer's website.

"I'll do it for them but it will cost $50 every time I do it," says Dominguez.

Updating databases will save owners hundreds of dollars each year. They will no longer have to spend time and money moving the airplane to and from an avionics shop for the update service.

Doing It Yourself Learning how to and actually performing even four or five of the 32 preventive-maintenance tasks listed in Appendix A of FAR Part 43 does add to the challenge of aircraft ownership, but not without substantial rewards.

The first reward is the confidence that comes from knowing your way around your airplane. It's comforting to launch out on an hourlong weekend flight — or on a much-anticipated three-week flying vacation to Alaska — with the feeling that you're capable of managing minor airplane maintenance glitches that crop up in spite of the most carefully laid plans. The second payoff (maybe it's the first) is saving money on maintenance.

You'll need to find a competent, understanding and patient A&P to teach you the skills needed to become a mechanically involved airplane owner. Ask around at your local airport. You're looking for a benevolent dictator-type mechanic. He or she must be dedicated to quality and be honestly interested in helping you. Once you have a couple of names, call and speak to your prospects, telling them that you want help learning how to safely work on your airplane. If they're agreeable, make an appointment to interview them.

When you arrive, take a good look around the shop. Is it clean enough and organized enough to give you confidence? If so, tell your prospect what you want. Most A&P technicians like working with willing and capable owners. But let's be clear — you're being evaluated too. I always enjoy working with owners, but that interest cools rapidly if I see that they don't respect my tools, maintain the cleanliness of my shop, exhibit good work habits or aren't willing to follow directions. The world of airplane maintenance does require a willingness to do things by the book.

The Performance Standard FAR Part 43 is titled "Maintenance, Preventive Maintenance, Rebuilding and Alteration." Portions of the 17 paragraphs and six appendices in this part specify who can do what types of maintenance, the definitions of major and minor alterations and repairs and what's required as far as record-keeping after maintenance. One of the most important paragraphs is 43.13 — "Performance Rules."

This paragraph says that work must be done using methods, techniques and practices prescribed in the manufacturer's maintenance manuals or other approved data. It also says that each person doing work on an airplane shall do that work in such a manner and use material of such a quality that the condition of the work shall be at least equal to the original condition. What's that mean?

Let's say Joe Owner decides to change a nose landing-gear tire, a task that's permitted under the PM rules. Upon reviewing the tire-changing tips in the FAA-approved aircraft maintenance manual, he learns that during the wheel reassembly operation, the bolts securing the two wheel halves must be retorqued to 90-inch pounds. To comply with the maintenance standard, Joe must have access to a calibrated torque wrench. Wheel half bolts are loaded in shear; this application does not require clamping (tension) loads.

During the inspection phase of the tire change, Joe finds that one of the wheel half through-bolts is severely rusted; can Joe boogie down to the local hardware store for a replacement bolt? No way. The replacement bolt must be identifiable as an aircraft-quality part.

The two examples are cited to show that a high standard of performance must be maintained. Few owners have enough experience in the airplane maintenance world to perform these tasks without coaching. That's where the benevolent dictator-style mechanic comes in.

He's your mentor. If you learn well and pay attention, it won't be long before you're trusted with more technical tasks. Airplane maintenance is not rocket science — it's really a balancing act between doing no harm and efficiently troubleshooting and making repairs. Coaching is needed because airplanes are a curious mix of toughness required to fly for thousands of hours and areas so breakable that a misplaced hammer blow or an over-torqued fastener will result in damages that require hundreds of dollars and hours of labor to repair.

Many owners who begin learning PM tasks soon find that they enjoy and want more of the sharply defined what-you-see-is-what-you-get world of aero maintenance. Indeed, according to Part 43.3 paragraph (d), any person working under the supervision of an A&P (or other holder of a repairman certificate) may perform any task that the supervisor is authorized to perform, if the supervisor observes the work to the extent necessary to ensure that it's being done properly. It's not uncommon for competent owners to do almost all the tasks in an annual inspection.

The Paperwork Doing your own maintenance is not nonstop fun; broken fingernails, head dings from standing up too quickly under a prop and a fine lattice of safety-wire cuts on each hand top the list of drawbacks. But to many owners, these are less worrisome than the burden of "signing off" PM tasks.

The FAA wants signoffs in the airplane records after maintenance. Part 43.9 says entries must consist of a description (or reference to data acceptable to the FAA) of the work performed; the date the work was completed; and the name, type of certificate and certificate number of the person completing the maintenance.

Let's be clear on this data-entry business. The entry applies only to the work performed. If a tire was changed, the tire change is the only thing the signoff covers.

Here's an example of an acceptable entry for a main tire change.

November 15, 2010: Replaced the main tire (6.00 x 6, 6 P.R.) and tube (6.00 x 6) in accordance with (often abbreviated as I/A/W) chapter 32-40-01 and 32-40-02 in Mooney M20K maintenance and M20K parts manuals. Joe Pilot Private 123-45-6789

There are other money-saving resources for aero-maintenance neophytes. The best low-cost sources of inspiration and technical knowledge are type clubs. In exchange for a nominal yearly fee, aircraft owners can get on the Internet — from almost anywhere — and gain access to vast accumulations of model-specific and task-specific technical information. There's either a type club or an expert for almost every popular aircraft still plying the skies.

If you want to learn more about airplane maintenance, I recommend getting on Amazon or any used-book site and searching for the out-of-print books in the Light Plane Maintenance Library series. Kas Thomas and other editors at Light Plane Maintenance authored the series. A good starting place is Rules and Inspections.

One last word on this subject. One of the most grievous and dangerous errors owners make when they start to do their own maintenance is failing to understand how important it is to get their work inspected. The cornerstone of aircraft safety is redundancy — the "second set of eyes" inspection principle is a non-negotiable one.

Get your training, stay disciplined, get help when you need it and stay safe.

Go to for a list of the FAA’s preventive-maintenance tasks.


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